The present invention relates to a connecting member for a flat circuit member and a method of connecting the connecting member and the flat circuit member, and more particularly to a connecting member for a flat circuit member which can be electrically connected reliably to a conductor portion in a flat circuit member such as a flexible printed circuit (FPC), a flexible flat cable (FFC), and a ribbon cable as well as a method of connecting the same.
Referring to FIGS. 18, 19, and 20, a description will be given of a conventional connecting member disclosed in JP-A-4-8372U. FIG. 18 is a perspective view illustrating a connecting member (electric connection member) 1; FIG. 19 is a cross-sectional view, taken in the direction of arrows along line XIX—XIX, of the connecting member 1 shown in FIG. 18 and illustrating the cross section of a flat circuit member (FFC) 10; and FIG. 20 is an enlarged cross-sectional view illustrating a state in which the connecting member 1 is used.
As shown in FIG. 18, the connecting member 1 has a bottom plate portion (proximal portion) 2, a plurality of claw portions (crimping pieces) 3 rising from both side edges of the bottom plate portion 2 in the thickness direction, and an arcuate contact portion 4 provided projectingly on the bottom plate portion 2.
When the connecting member 1 is connected to the flat circuit member 10, after the connecting member 1 is first located below the flat circuit member 10, the claw portions 3 of the connecting member 1 are caused to penetrate first piercing portions (portions of an insulating portion (insulating coating) 11 in FIG. 19) of the flat circuit member 10 as shown in FIG. 19. Subsequently, the claw portions 3 are bent toward the bottom plate portion 2 in such a manner as to clamp the flat circuit member 10 between the arcuate contact portion 4 on the bottom plate portion 2 and the claw portions 3. At this time, as shown in FIG. 20, the insulating portion 11 of the flat circuit member 10 clamped between the claw portions 3 and a concave arcuate surface 5 formed in advance on the arcuate contact portion 4 is peeled off by distal edges of the claw portions 3. A conductor portion 12 of the flat circuit member 10 thereby exposed and the claw portions 3 of the connecting member 1 are brought into contact with each other, thereby electrically connecting the flat circuit member 10 and the connecting member 1.
Incidentally, if it is assumed that, as shown in FIG. 20, the width of the connecting member 1 is W1, the bent width W2 of the claw portion 3 which is bent with a dimension of curl R becomes approximately one half of the just-mentioned width W1 of the connecting member 1 (i.e., W2≈W1÷2).
Although a description has been given above of the connection of one connecting member 1 to one conductor portion 12 formed in the flat circuit member 10 by referring to FIGS. 18 to 20, actually there are cases where a plurality of conductor portions 12 are formed in or on the flat circuit member 10 (see FIGS. 19 and 20). In this case, the plurality of connecting members 1 are respectively connected, as described above, to the plurality of conductor portions 12 requiring connection.
In a case where the interval between adjacent ones of the plurality of conductor portions 12 in the flat circuit member 10 is small and the width of each conductor portion 12 is narrow, each connecting member 1 must be made compact correspondingly. However, in conjunction with this miniaturization, the width W1 of the connecting member 1 becomes narrow, and therefore the dimension of curl R of the claw portion 3 must also be made small. In such a connecting member 1, there is a possibility that it becomes difficult to bend the claw portion 3 smoothly. In addition, since the width W1 of the connecting member 1 becomes narrow (i.e., the width of the bottom plate portion 2 becomes narrow), it becomes difficult to form the arcuate contact portion 4 on the bottom plate portion 2. Accordingly, there is a possibility that it becomes impossible to obtain stable electric contact between the claw portion 3 and the conductor portion 12. Even if the flat circuit members 10 with a plurality of such contact members 1 are manufactured, their quality control is troublesome or difficult, thereby resulting in an increase in the manufacturing cost.